Here are some of my notes on sensitivity and specificity:
Sensitivity (true positive rate) refers to the percentage of children who are correctly identified as meeting criteria for a condition; VALUABLE FOR CONFIRMING DX; 80% sensitivity is preferable.
Specificity (true negative rate) refers to the percentage of children without problems who are correctly identified as such; VALUABLE TO RULE OUT THE PRESENCE OF A CONDITION; 90% is preferable for a diagnostic test.
There is always a “trade-off” between sensitivity and specificity: for a screening test in which early diagnosis is beneficial and when it is desirable to identify all those at risk for having a condition, high sensitivity is preferable to higher specificity.
**For the TIMP, Specificity is higher, indicating that it is a good measure for detecting large numbers of high risk infants who are not developing typically and have delayed posture and motor development, which is it’s intended purpose. It is not as sensitive for identifying CP.
**The AIMS has been found to be more beneficial when administered at critical age ranges. While the 5th centile cut off value is best to identify the most delayed children (and those likely to have CP), the 10th centile cut off is best for identification of the greatest # of infants with abnormal motor development.
-AIMS at 4 months: 10th Centile: best combination of sensitivity/specificity
-AIMS at 8 months: 5th Centile: better specificity to identify CP; 10th Centile: better sensitivity to identify greatest # of
infants with abnormal gross motor development